Opal from selected localities.
Italy | |
| "Giorgio Bortolozzi (visual identification)" |
Marchesini, M., Pagano, R. (2001) The Val Graveglia manganese district, Liguria, Italy. The Mineralogical Record: 32: 349-379; 415. | |
"Giorgio Bortolozzi (visual identification)" | |
| Redazione (2005): Sistematica ligure: resoconto 2005. Notiziario di Mineralogia Ferrania Club, 19, 3-5. |
Cassagna Mine, Ne, Genoa, Liguria, Italy